RESOLV+

NAME
DESCRIPTION
CONFIGURATION
ENVIRONMENT VARIABLES
FILES
BUGS
AUTHOR
SEE ALSO

NAME

resolv+ - enhanced DNS resolver library

DESCRIPTION

Resolv+ is a modified version of the standard
Berkeley BIND host resolver library. Enhancements include
support for host lookups via the Internet Domain Name System
(DNS), the /etc/hosts file, and Sun's Network
Information Service (NIS).

The programmer interface to the resolv+ routines is
identical to that of the standard resolver library. For
further information see the appropriate manual
pages.

CONFIGURATION

As with the standard resolver library, the file
/etc/resolv.conf must be set up before the resolver
can function. In addition, the file /etc/host.conf
contains configuration information specific to
resolv+.

The host.conf file should contain one configuration
keyword per line, followed by appropriate configuration
information. The keywords recognized are order , trim ,
multi , nospoof , and reorder . Each keyword is
described seperately below.

order

This keyword specifies how host lookups are to be performed.
It should be followed by one or more lookup methods,
seperated by commas. Valid methods are bind , hosts
and nis .

trim

This keyword may be listed more than once. Each time it
should be followed by a single domain name, with the leading
dot. When set, the resolv+ library will automatically trim
the given domain name from the end of any hostname resolved
via DNS. This is intended for use with local hosts and
domains. (Related note: trim will not affect hostnames
gathered via NIS or the hosts file. Care should be taken to
insure that the first hostname for each entry in the hosts
file is fully qualified or non-qualified, as appropriate for
the local installation.)

multi

Valid values are on and off . If set to
/etc/hosts
file, instead of only the first. This is off by default, as
it may cause a substantial performance loss at sites with
large hosts files.

nospoof

Valid values are on and off . If set to
rlogin
and rsh. It works as follows: after performing a host
address lookup, resolv+ will perform a hostname lookup for
that address. If the two hostnames do not match, the query
will fail.

alert

If this option is set to
nospoof option is also set, resolv+ will log a
warning of the error via the syslog'' facility. The
default value is off.

reorder

Valid values are on and off . If set to
''

ENVIRONMENT VARIABLES

The following environment variables may be set to override
resolv+'s configured behavior:

RESOLV_HOST_CONF

If set, it will override the default filename
(

RESOLV_SERV_ORDER

If set, will override the

RESOLV_SPOOF_CHECK

If set, will override the spoof check flag. Valid values are

RESOLV_ADD_TRIM_DOMAINS

If set, contains a list of domains to trim that will
augment, not supersede, the list in the host.conf
file.

RESOLV_OVERRIDE_TRIM_DOMAINS

If set, contains a list of domains to trim that will
override those in the host.conf file.

RESOLV_MULTI

If set, overrides the

RESOLV_REORDER

If set, overrides the

FILES

/etc/host.conf, /etc/hosts

BUGS

Quite possibly.

AUTHOR

The original BIND resolver library comes from the University
of California at Berkeley's Computer Science Research Group.
The original resolv+ modifications were made by Bill Wisner

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